US2460809A - Method of preparing gelatin - Google Patents

Description

Patented Feb. 8, 1949 2,460,809 METHOD or PREPARING GELATIN Rudolph E. Damschroder and. Marie E. Kantiman, Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey.

No Drawing.

Application February 7, 1946,

Serial No. 646,211 r en the time of treatment sharpeners have been added to the liming suspension employed for that purpose. After treatment with the lime, the hide or bone stock may then be treated with acid to remove the lime, followed by extraction of gelatin therefrom with hot water. In addition to its being a long drawn-out process, also in the previous operations, there was often danger of loss of gelatin in the acid treatment which tends to hydrolyze the collagen present, thus forming material which may be washed out in the washing operations. c 1 J One object of our invention is to provide an improved method of preparing gelatin from gelatin-containing material. Another object of 'our invention is to eliminate the liming step in me paring gelatin from hides or bones. A further object of our invention is to provide a method of preparing gelatin in which the organic inaterial from which the gelatin is to be obtained is dissolved and the gelatin is separated. there from. Other objects of our invention will appear herein.

We have found that the organic constituents of gelatin-containing materials can be dissolved in a water solution of ammonia or a lower aliphatic amine, such as methyl amine, dimethyl amine, or ethyl amine, in which dissolving-operation collagen is converted to gelatin and 1 the gelatin thus obtained can be separated from the solution and employed as desired.

In proceeding in accordance with our invention, it is desirable that the gelatin-containing materials be first divided into small units'sothat the dissolving action may readily take place. For instance if the particles to be treated are 50 mesh or finer, the dissolving action may take place in a few minutes. If the particles-are as much as 20 mesh, the dissolving action is slower and with still larger units, a still slower dissolving action occurs. For instance, if a material such as hides be in the form of pieces as much as A inch in diameter, it may take as much as an hour to dissolve that material. Thedisadvantage-of a long time of dissolution is that the material which dissolves first is being subjected to-hydrolysis during the dissolving of..the remainder of the material and, therefore,;that-gelatin; is

hydrolyzed morethanis desired for, auniform product. If the presence of some excessively hy drolyzed gelatin is not objectionable in the final product, the use of small particles of hide or bone as the starting material is not so important.

Our invention is applicable to obtaining gelatin from gelatin-containing materials generally, whether wet, dried, or salted, but particularly from bones. The hides employed may be on the one hand green calfskins won the other hand old, dried hides, such as dried bufialo skins. In the case ,of calfskins or the like which are more susceptible to the dissolving of organic matter dissolution will take place in a short time, whereas with hides which are dry, horny, and thick, the dissolving action may be slow, although a fine particle size of this material will speed up the action. Other gelatin-containing materials, such as raw bones or sinewsJeet, tails, or other parts of cattle, sheep, or other animals may be treated by our process, although with many of these the gelatin obtained will not be in nearly as high a degree of refinement was that obtained:

from for instance, hides.

The agent which is employed to promote the dissolving operation may be ammonia or an aliphatic amino compound of notmore than three carbon atoms or a mixture of these agents. Some of the amino compounds which have been found to be particularly useful for this purpose are the following: ammonia, methylamine, dimethyls amine, ethylamine, ethylene diamine, ethanolamine, propanolamine, propylene diamine.

It is desirable to have a concentration of at least 10% of the amine or ammonia in water in order to promote the dissolving ofthe organic matter of the gelatin-containing material. As a rule, it will be preferable to operate the process with concentrations of less than 30% of ammonia or amine, We have found, however, that concentrations less than 10% are operative and their use is within the scope of our invention. For instance, a 3% solution may be employed for the dissolving operation although a time of two hoursmay be necessary with a readily treatable material as compared with 10 or 20 minutes with concentrations of amine or ammonia within the preferred range. The lower limit of concentration which will dissolve the. gelatin-forming material as-specified above appears to be about 1% of amine or ammonia. I

Although We have found that the dissolving of that organicmatter of gelatin-containing material in accordance with our invention takes place satisfactorily at temperatures in the yicinity :of R, such as l20-140 other temperatures may also bee'mploy'e'd, the'time of dissolving the material depending not only on thetemperature but also upon the condition or the material, its particular size, and T the concentration of a'rnin'e prior art, were ground so that they would pass a mesh finer than 50. This ground, acidulated bone was agitated in a water solution of methyl amine of 12% concentration for ten'minutes at 130 F., whereupon the acidulated bone was dissolved. The thus-formed solution was evacuated by means of an aspirator pump to a vacuum of 30-40 mm. of mercury for twenty-five minutes at 130-140" F. This treatment reduced the methylamine content to about 1% of the original content of methylamine. The pH of the solution was adjusted to 6.0 by the addition of a small proportion of sulfuric acid, and the solution obtained was filtered. This solution was then set by cooling and the resulting gelatin obtained was washed and dried. I

Example 2.Ground, acidulated bone was agitated in a 28% solution of ethylamine for ten minutes at 130 F. whereupon a considerable fraction of the bones dissolved, This solution was evacuated by means of an aspirator pump for twenty-five minutes at 130-140. F. This reduced the ethylamine content to about 1-2% of the original. The pH of the solution was adjusted to 6.0 by addition of sulfuric acid and this solution filtered. The chilled set gelatin solution was then dried.

Example 3.--Dry bones as obtained by degreasing bones as described in the prior art were ground so that they would pass a mesh finer than 50. This ground non-acidulated bone was treated the same as in Example 1, and by such treatment, gelatin was obtained albeit poor quality.

Example 4.-Dry, acidulated bones were dis- 1 solved in 100% ethylenediamine in 48 hours at C. This solution was filtered and then diluted with 4-6 volumes of ethyl alcohol. The precipitated gelatin was dissolved in water, set by chilling, washed and dried.

Example 5.-Finely divided Water buffalo hide was treated with 12% methylamine solution for sixty minutes at 135 F., whereupon the hide dissolved. This solution was evacuated twentyfive minutes at a pressure of -40 mm. of mercury at a temperature of 135 F. This treatment reduced the amine content to about 1% of the original. The pH of the solution was adjusted to 6.0 by the addition of a small amount of sulfuric acid. The solution was then gelled by chilling and dried.

Example 6.-Finely divided acidulated bones were agitated in a 12% ammonia solution for twenty minutes at 135 F. whereupon the acidulated bones dissolved. Evacuation of this solution for fifteen minutes at 135 F. at a pressure of 30 mm. of mercury reduced the ammonia content to less than 1% of the original. This solution gelled on cooling and was then dried.

Example 7.--Tne same procedure as described in Example 6 can be used substituting a solution made 6% with respect to ammonia and 6% with respect to methylamine.

Example 8.Acidulated bones were agitated in a 12% solution of ammonia, bufiered to a pH of 9.5 to 10.0 by appropriate amounts of an ammonium salt, such as ammonium carbonate, ammonium sulfate, ammonium acetate, or ammonium chloride, for thirty minutes at 140 F. whereupon a considerable portion of the bones dissolved. Several techniques were used to recover the gelatin.

(a) Additional salt, i. e., (NH4)2SO4 was added, sufiicient to precipitate the gelatin at the abovementioned pH values. This coagulated gelatin was washed free from salts, dissolved in water, set and dried.

(b) The pH of the salt gelatin solution was lowered to the point where the gelatin separated from solution. This coagulated gelatin was treated as in (a) (c) The gelatin salt solution was chilled at the pH of the reaction and the set gelatin washed free of salt before drying.

We claim:

1. A method of obtaining gelatin from collagen-containing parts of the animal body which comprises subjecting such parts to the dissolving action of an aqueous solution of 1-30% concentration of an aliphatic amine selected from the group consisting of methylamine, dimethylamine, ethylamine, ethylene diamine, ethanolamine, propanolamine, and propylene diamine, whereby the collagen is dissolved and converted into gelatin.

2. A method of obtaining gelatin from collagen-containing parts of the animal body which comprises subjecting such parts to the dissolving action of an aqueous solution of l-30% concentration of methylamine whereby the collagen is dissolved and converted into gelatin.

3. A method of obtaining gelatin from collagencontaining acidulated bone which comprises subjecting the acidulated bone to the dissolving action of an aqueous solution of l30% concentration of methylamine whereby the collagen is dissolved and converted into gelatin.

4. A method of obtaining gelatin from collagen-containing animal hide which comprises subjecting the hide to the dissolving action of an aqueous solution of l-30% concentration of methylarnine whereby the collagen is dissolved and converted into gelatin.

5. A method of obtaining gelatin from collagen-containing parts of the animal body which comprises subjecting such parts to the dissolving action of an aqueous solution of methylamine of 130% concentration and a. buffering agent selected from the group consisting of ammonium and amine salts whereby the collagen is dissolved and converted into gelatin, separatin the resulting solution from any insoluble material therein followed by insolubilizing the gelatin and washing free of the salts therein.

6. A method of obtaining gelatin from collagen-containing parts of the animal body which comprises subjecting such parts to the dissolving action of an aqueous solution of 1-30% concentration of a mixture of methylamine and ammonia, the amount of methylamine being at least equal to the amount of ammonia, whereby the collagen is dissolved and converted into gelatin.

R. E. DAMSCHRODER. MARIE E. KAUFFMAN.

REFERENCES CITED The following references are of record in the file of this patent: